1dumrednek

i was on my way home last night pulling the flat deck (after hauling buddy's duramax to the city ) and my check gauges light came on and the voltage meter dropped right to 0. i got out and tapped on the alternator and shut the truck off and fired it up again and it worked good for 20 minutes and cut out again. not all the trailer lights were working so i thought it might be a short in the trailer so i unhooked that and tapped the alternator agin and it worked good for a couple hundred km. it cut out again juat as i pulled in the yard last night and i cant get it to work any more. tried blowing it out and spraying wd40 into it but nothing.

is my alternator shot?

thanks

Robert Rausch

Sounds to me like it might be a connection or maybe the internal voltage regulator, which can be replaced.

Ruralmedic

I believe alternator voltage is regulated externally by the PCM. When mine went out, it was the diode plate within the alternator that was shot, the brushes happened to be fine. Had it repaired at a local shop for around $60.

I would check to see if there is any voltage output at the alternator with a voltmeter to rule out a connection problem. If none, then it probably needs to be rebuilt or replaced. There are rebuild kits available to do-it-yourself.

Good luck!